We're dividing 12507854 by 129 
The aim is to understand the frequency of 129 in 12507854.

Let's proceed to step 1:
129 can be fit into 1 0 times, resulting in a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Include the next digit (2) from the dividend after 1, then repeat: 12 / 129

Let's proceed to step 2:
129 goes into 12 0 times with a remainder of 12.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 12, we end up with 12.
Append the next digit (5) from the dividend to 12 and continue with: 125 / 129

Advancing to step 3:
The number 129 fits into 125 0 times, leaving a remainder of 125.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 125 and we're left with 125.
Include the next digit (0) from the dividend after 125, then repeat: 1250 / 129

Going ahead to step 4:
1250 divided by 129 is 9 with a remainder of 89.
Use 9 as the next digit of our solution. 
Result so far: 9.0
If we take 1161 away from 1250, we end up with 89.
Bring next digit (7) of the dividend behind the 89 and repeat the process: 897 / 129

On to step 5:
897 divided by 129 is 6 with a remainder of 123.
The next digit of our result is 6. 
Result so far: 96.0
If we subtract 774 from 897, we get 123.
Bring next digit (8) of the dividend behind the 123 and repeat the process: 1238 / 129

Moving on to step 6:
When dividing 1238 by 129, we get 9 with a remainder of 77.
Put 9 as the next digit of the answer. 
Result so far: 969.0
Deduct 1161 from 1238 and we're left with 77.
Take the next digit (5) from the dividend and append it to 77, then repeat: 775 / 129

Let's proceed to step 7:
775 divided by 129 is 6 with a remainder of 1.
Record the quotient 6 as the next digit in the result. 
Result so far: 9696.0
If we take 774 away from 775, we end up with 1.
Take the next digit (4) from the dividend and append it to 1, then repeat: 14 / 129

Going ahead to step 8:
When dividing 14 by 129, we get 0 with a remainder of 14.
The next digit of our result is 0. 
Result so far: 96960.0
Subtract 0 from 14 to get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Going ahead to step 9:
If we divide 140 by 129, we get 1 and a remainder of 11.
Put 1 as the next digit of the answer. 
Result so far: 96960.1
Deduct 129 from 140 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Step 10:
If we divide 110 by 129, we get 0 and a remainder of 110.
Record the quotient 0 as the next digit in the result. 
Result so far: 96960.1
Deduct 0 from 110 and we're left with 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1100, and continue the process.

Let's proceed to step 11:
129 can be fit into 1100 8 times, resulting in a remainder of 68.
The next digit of our result is 8. 
Result so far: 96960.108
If we subtract 1032 from 1100, we get 68.
Since there are no more digits in the dividend, we add a zero to the remainder making it 680, and continue the process.

Moving on to step 12:
680 divided by 129 is 5 with a remainder of 35.
Write down 5 as next digit of the result. 
Result so far: 96960.1085
If we take 645 away from 680, we end up with 35.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

On to step 13:
The number 129 fits into 350 2 times, leaving a remainder of 92.
Record the quotient 2 as the next digit in the result. 
Result so far: 96960.10852
If we take 258 away from 350, we end up with 92.
Since there are no more digits in the dividend, we add a zero to the remainder making it 920, and continue the process.

Step 14:
920 divided by 129 is 7 with a remainder of 17.
The next digit of our result is 7. 
Result so far: 96960.108527
The remainder is 17 after subtracting 903 from 920.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Let's proceed to step 15:
170 divided by 129 is 1 with a remainder of 41.
The number 1 becomes the next digit in our result. 
Result so far: 96960.1085271
The remainder is 41 after subtracting 129 from 170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 410, and continue the process.

Advancing to step 16:
When dividing 410 by 129, we get 3 with a remainder of 23.
Record the quotient 3 as the next digit in the result. 
Result so far: 96960.10852713
Deduct 387 from 410 and we're left with 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

The quotient of the division is 96960.10852713, and the remainder is 2.3e-08.